Head-mounted displays (HMDs), near-eye displays, and other kinds of wearable display systems can be used to provide virtual scenery to a user, or to augment a real scenery with additional information or virtual objects. The virtual or augmented scenery can be three-dimensional (3D) to enhance the experience and to match virtual objects to the real 3D scenery observed by the user. In some display systems, a head and/or eye position and orientation of the user are tracked in real time, and the displayed scenery is dynamically adjusted depending on the user's head orientation and gaze direction, to provide experience of immersion into a simulated or augmented 3D environment.
It is desirable to reduce size and weight of a wearable display. Lightweight and compact near-eye displays reduce the strain on user's head and neck, and are generally more comfortable to wear. Typically, an optics block is one of heaviest modules of the display. Compact planar optical components, such as waveguides, gratings, Fresnel lenses, etc., can be used to reduce size and weight of an optics block. However, compact planar optics may be prone to optical distortions and aberrations.